Bowling pin respotter



April 14, 1953 c. E. SCHON BOWLING PIN RESPOTTER:

5 Sheets-Sheet 1 Filed July 27, 1946 INVENTOR CHARLES E. SCHON B ATTORNEY 5 Sheets-Sheet 2 April 14, 1953 c. E. SCHON- BOWLING PIN RESPOTTER Filed July 27, 1946 FIG. 3

ATTORNEY 5 Sheets-Sheet 3 Filed July 27, 1946 FIG. 6

SUPPLY LINE 4INVENTOR CHARLES E. SCHON BY em, \9

ATTORNEY April 14, 1953 c. E. SCHON BOWLING PIN RESPOTTER 5 Sheets-Sheet 4 Filed July 27, 1946 INVENTOR CHARLES E. SCHON B ATTORNEY Aprxl 14, 1953 c. E. SCHON. 2,634,979

BOWLING PIN RESPOTTER Filed July 27, 1946 5 Sheets-Sheet 5 Illil JOY/2 26 2 INVENTOR.

- CHARLES E. SCHON YW$M A'ITORNEY Fig. '7 is a front elevation, partly in section, of a pair of pin grippers, illustrating a modified form of operating mechanism for the same;

Fig. 8 is a sectional side elevation of a said mo dii'led form, taken on line 8-3 of Fig. 7;

Fig. 9 is a sectional front elevation of a pair of pin grippers, illustrating another modified form of pin gripper operating mechanism;

Fig. 10 is a sectional side elevation of said modified grippers, taken on line Itlii of Fig. 9; and

Fig. 11 is a sectional side elevation of the same type of gripper illustrated in Fig. 10 with the exception of showing the same connected to operating cylinders which are located off-center.

The pin respotting device consists of a table which, by means of a pair of protruding lugs 22 (Fig. 3) and a pair of suitable studs or shafts 24, is attached to a pair of guide shoes 26 and 28. Suitable cables 2? are connected to guide shoes 26 and 28 which engage with vertical guide channels 39 and 32. Cables 21 lower and raise the table 20 in proper time relation with the operation of the bowling pin setting machine, in a manner similar to thatdisclosed in U. S. Patent No. 2,208,605 issued to Mr. G. J. Schmidt on July 23, 1940.

To the bottom side of said table 20 is secured a mat 34 of resilient material such as soft or sponge rubber or other suitable material. The table 20 is provided with narrow slots 36 through which protrude the shanks 33 of the pin gripper bars 40. The slots are of such narrow width that the head of a bowling pin would not project through the same if a pin should be positioned below the slot when the table 26 is lowered into engagement with standing pins. Each shank 38 has secured to its lower end a gripper bar 40. Inasmuch as the illustration is based on a tenpin bowling game, the table 2!) is equipped with ten pairs of pin grippers, each pair consisting of two coacting gripper bars '42. For the purpose of illustration, the gripping surfaces 4! of the gripper bars 40 in Fig. 1 have a contour which fits the surface of the handles of the pins P; however, the contourof the gripping surfaces could be round, half-round or any other shape suitable for satisfactory engagement with a bowling pin.

In order to provide the grippers with the greatest possible range for gripping pins that have moved or walked off varying distances from their original spotted position, the shanks 38 of adjoining grippers are staggered to permit alignment with one another when in their most open position. By aligning the shanks 38, as shown in Fig. 2A, the gripper bars 40 of adjoining grippers, when in their most open position will be close together. With this construction, there is a wider range of coverage and it will be very rarely that any standing pin moves so far from its spotted position that the descending gripper bars 40 will engage with the head of the standing pin.

The gripping surface 4I of the gripping bars 40 is finished with a suitable material which will groove or channel 46 in the top portion of table,

20 and a pair of guide bars 48 (Figs. 2, 3, 4 and 5) Each trolley 58 is provided with suitable rollers 62 which engage with said cross bar thus permitting the trolley to move horizontally. A separate trolley is provided for each of the ten pairs of grippers.

The arrangement of the pins in a ten-pin bowling game is such that four rows of pins are formed: namely, No. I pin in the first row; Nos. 2 and 3 pins in the second row; Nos. 4, 5 and 6 pins in the third row; and Nos. 'I, 3, 9 and I9 pins in the fourth row. The carriages or trolleys 58, therefore, are also arranged in rows with four cross bars 69 employed to suspend said trolleys, each cross bar being located in the center line above a row of pins. These four cross bars to are welded together into a frame which, by means of suitable brackets 68, is mounted to the lower side of a table top plate "it. The plate IE1 is connected to and supported by three operating lugs I2, the protruding hubs T3 of each being fastened to the upper end of a Vertical shaft I4. The lower end of eachshaft 74 carries a piston I5 (Fig. 1) which engages with the walls of a vertical cylinder '53, all three of which are secured to the top side of table 29.

Each cylinderll, at its top portion, is provided with a port as (Fig. 1) and, at its bottom portion, with a second port 32. All ports 30, by means of flexible tubings 84, are connected to a manifold 88; While all ports 82, by means of flexible tubings 88, are connected to a manifold 99. Both manifolds may be conveniently attached to a suitable portion of the main frame (not shown) of the automatic bowling pin setter.

Manifold 86 (Fig. 6) by means of a flexible hose 92, is connected to a port 94 of a conventional type slide valve 96; and manifold 90, by means of a flexible tubing 98, is connected to a port HID of the aforementioned slide valve 96.

The slide valve 86 consists of a cylinder I02 and a three band spring tensioned valve plunger I04. The plunger I94 on one end is provided with an operating member It, protruding from said cylinder. The operating member I05 carries a roller I08 which engages with a cam H0 mounted on a shaft H2 supported in suitable bearings (not shown) of the bowling pin setting machine. ,Roller IE8 is maintained in constant engagement with cam IIII by means of spring I09 acting on the opposite end of plunger I04 as shown in Fig. 6. Shaft H2, by means of a sprocket I land a chain I I6, is driven in proper time relation from the main drive shaft (not shown) of the pin setting machine.

Slide valve 96 is provided with two exhaust ports H8 and I20, and a supply port I22. The supply port I22 is connected, by means of duct I24, to a source of supply of a fluid under pressure, such as compressed air. Other suitable fluids could also be used, in which case, the exhaust ports would be connected to a suitable reservoir (not shown) to receive the discharged fluid. Exhaust port H8 serves manifold 86; while exhaust port I20 serves manifold 90 at the proper position of valve plunger I04.

" Suitable guiding mechanism is provided to ren- Fig. 3. The table, on its lower side, is also equipped with a cushion or mat I12 of resilient material, such as rubber, or other suitable material.

The elongated gripper bars I62, preferably extending lengthwise of the alley bed B, are secured to the lowermost ends of vertical shanks I14 protruding through suitable slots I16 in table I16. The upper portion of each shank I14 is attached to the bottom portion of a dove-tailed operating shoe I18 which is slidably mounted in the track formed by a channel I80, in the top side of table I10, and suitable guide bars I82 secured to the same. To the top side of each operating shoe H6 is mounted a bracket I84 with a piston rod I86 pivoted to its free upper end. To the other end of each piston rod I86 is attached .a piston I64, mentioned above.

The action of all pistons is controlled by means of a slide valve I88 (Fig. 9) which is of the same type and construction as that shown in Fig. 6. The valve I68 consists of a cylinder I90 and a three band valve plunger I92 provided with an operating member I94 which protrudes from one end of said cylinder I90. Member I94 carries a cam roller I96 which contacts an open cam I98 mounted on a shaft 200, driven by means of a sprocket 202.and a chain. 204, in proper time relation from the main drive of the bowling pin setting machine (not shown).

The slide valve I88 is provided with a supply port 266 which is connected to a source of supply (not shown) of compressed air, oil or other suitable fluid by means of a tube or pipe 208. Said valve has, furthermore, a port 2I0 and a port 2I2. Port 2I2, by means of a tube 2I4, is connected to a distribution pipe 2I6 having outlets leading to the cylinders which operate the pin gripper members at each pin spot position on the bowling alley. Tubes 2I8 are provided to connect the distribution pipe 2I6 which the bottoms of all pistons I64. Port 2I0, by means of a tube 220, is connected to a distribution pipe 222 having outlets leading to the cylinders which operate the pin gripping members at each pin spot position on the bowling alley. Tubes 224 are provided to connect the distribution pipe 222 with the tops of all pistons I64.

Therefore, if compressed air is forced through port 2I2 and tubes 2I8 against the bottoms of all pistons I64, the pistons I64 will be moved toward the opposite ends of the cylinders. This motion will, in turn, actuate, through the various pise tons rods I66, the bowling pin grippers I62 and bring them together into gripping relation. When compressed air is forced through port 2I6 and tubes 224 against the tops of all pistons, the grippers of each pair of grippers I62 Will be moved away from each other, thus effecting a release of gripper bars I62 from the standing pin P. Slide valve I88 is, furthermore, provided with two exhaust ports 226 and 228. Port 228, at the proper position of valve plunger I92, permits the compressed air in pipes 222 and 220 to escape; while exhaust port 226 serves the same purpose in conjunction with pipes 2 I 6 and 2 I4.

In using fluids other than air, suitable conduits will be connected to ports 226 and 228 leading to a reservoir so that the fluid can be reused to operate the pistons I64. A spring 230, provided in cylinder I90 of valve I88, acts upon the bottom of valve plunger I92 and serves the purpose of keeping roller I96 in constant contact with the cam, I98.

sion or pressure of the grippers can be regulated easily by changing the pressure of the compressed air. This feature has the advantage of minimizing wear and tear on the bowling pin and automatically takes into account variations in the diameters of thenecks of bowling pins. Furthermore, if an obstruction should be encountered by the bowling pin grippers, they would automatically stop before any damage could be done.

The operation of this type of gripper mechanism, just described, is as follows:

After the first ball is thrown and some pins remain standing, the table I10 descends and clamps the standing pins to the alley bed in the same fashion as previously mentioned. The head portions of the standing pins embed themselves partly into the mat I12. This feature enables pins of various lengths to be securely held against lateral movement.

The valve plunger I92 is then actuated by the cam I98 to apply pressure to the bottoms of all pistons, thereby causing the gripper bars I62 to be advanced toward the standing pins and grip the same.

In the case of an oil spot pin, one gripper bar contacts the clamped pin first and stops. The air pressure, however, keeps the second piston moving until the second grip er bar also contacts the standing pin. The pin is then firmly gripped between two yielding grippers.

After the pins are firmly gripped by said gripper bars, the table I10 moves upward and permits the fallen pins to be removed from the alley by a sweep or other suitable means. After this operation, the table I10 descends again and respots the pins on the alley in the same position they occupied before they were removed from the alley.

The slide valve I88 is then shifted through the coordinated action of spring 230 and cam I98 and air pressure is applied to the tops of all pistons I64 to eifect a release of said pins, as mentioned heretofore. To provide noiseless and smooth operation, each shank I14 on its upper portion is provided with a rubber bumper 232 (Fig. 9). The bumpers 232 of opposing shanks I14 engage each other when no pin is standing to be gripped.

Due to the long stroke of gripper operating members I18, the latter and their operating cylinders cannot be placed in a row, but have to be staggered. Therefore, all gripper units which cannot be placed on the center line of the pin row must have a curved shank 234 which holds the gripper bar I62 as shown in Fig. 11. To avoid interference with the staggered arrangement of the dove-tailed operating shoes I18 of the pin gripper units,'all cylinder housings I68 which cannot be placed on the center line of the pin row are provided with a modified or oifset flange support 236 as shown in Figure 11.

The invention above described may be varied in construction within the scope of the claims, for the particular device selected to illustrate the invention is but one of many possible embodiments of the same. The invention, therefore, is not to be restricted to the precise details of the structure shown and described.

What is claimed is:

1. An automatic bowling pin raising and lowering mechanism for bowling alleys comprising, a platform mounted for vertical movement toward and away from an alley, a compressible member mounted on the under side of said platform, means for lowering the platform andsaid comnressible-member into clam-ping engagement-with alLstand-ingpins -onj-a bowlingalley to clamp the same betweenthebowlingalley and the-platform, pin-gripping members extending below said platfgrm and means for bringing said -members intogripping engagement with standing bowling p ns clampedbetween said platform'andbowling alley.

: 2: A; bowling pin ,handling apparatuscomprising, a; platform constructed and arranged to travel towardandaway from abowling alley; a

sponge ilike-member mounted'on' the under side of said platform, a carriageadaptedand arrangedfor horizontal' travel mounted above said platform; gripper; arms attached to said carriage having; pin gripping members extending below-= said platform, means for loweringsaidplatform and sponge-like member into clamping engagement--withpins standing-on a bowling alley to clamp the v bowling; pins-betweenthe bowling alley and the sponge-like member, and" means 'for bringing; said pin gripping members together into grippingiengagement with a pin standing on said bowling alley 'bymoving said arms toward each other.-

37, Automatic bowling pin apparatus comprising; a -table frame constructed and arranged for mpvementtoward-and away from a bowling alley,

cushioning material "mounted on the under side of-said frame; a traveling carriage mounted above said-table frame -for-horizontal movement with respectto said frameand having 'pinengaging members projectingbelow the cushioning; material; means-for lowering said frame-and cushioning-material mounted-on said; frame into en gagement with bowlingpinsstanding on the" area ofa bowling alley on which bowling pins; are spotted; a cushioning-member mounted on the under side of said-platform; elongatedslots formed-in saidplatform and'cushioningmaterial adj acentthe; areas on which" bowling pins are spotted a trolley-positioned above-each pin spot U position; trolleysupporting means -mountedabove-' s'aid platform constructed and.- arranged tapermit said trolleys-to move horizontallyabove said platform connecting links: pivotally connectedwatone end to-each ofsa'id-trolleys and atrathe: other end, to sliding supports coacting withssaidplatform; said .pivoted vconnecting links beings:constrncted and arranged to move said sunPQrts.arelative'gitozieach other as the distance between saidctrolley; support. and said "platform x dir arms Onnfictfidctoi said sliding supports ojecting-througl r-the slots fcrmed .in-said ei] aging me pins"--means for; firstilowering said platform-to va wnggthe p'latform .andithe gripped bowling pins to? e iallfini bowlingipins toibe removed from andsfonthen'dowering-saidsplatformto rpplacesthei-lifted zbowling -pins inane same po'si and; cushioningzi material; a bowling pi-n' be sri n neeted pito ..:thei IQXVQIU: end i on saidyarms means for: changingithe distance: between saidxtrolleysupports: and said platform "to ibrin 'gtheubowling .pin engaging members into gripping engagement-with thestanding-bcwling 70 spins ,standingioman alley; th'en elee:

1-0 7 tion they occupied" before theywerejliftedt and meansfor: changingithe distancebetween said carriage support and said=- platformi -to release: the bowling pin" grippers fromengagemenirwithf the'standin'g pins.- 7

5: In anapparatus for setting pins -uponithei bedof-=a-bowling alley; an elevator adapted -to' be raised and lowered; a carriage-support*com nected to said elevator for movement relatiyeto" the elevator; sliding-*members rmounted- 0n-said elevator; oarriages movably-mountedonsaid carriage support; arms connected-a to: said sliding members iprojecting below' the elevator,- a bowling 7 pin contacting device; formed: onithe lower endof-each-of-said arms-'to-grip a bowling-pin bet-ween saiddevicesrmeansinterconnecting said? carriages with saidsliding-members to vary-the distancebetweenfi said" sliding members as the distance between said carriage; support and 'e1e-- vator is-varied; "means for loweringsaidteleyator into engagement with; the heads of: bowlingins? standingon the alley toholdthepins,between-1 theelevator and thealley,- and means for" then. changing-the-distancebetweensaidcarriage'sup port and the elevatoif to" bring the bowling; pin" contacting devices intoengagement-withstanding bowlingpins,

" 6. An-apparatus-for setting pins-upon a-'bow1-- ing alley comprising, a pin; clamping :platform,v pairs-of I movable pin gripping members depend ing from saidplatform at each pin-spot position; separate compressible; fluidpressure means for yieldably movingaeaeh" pini gripping member "ofeachpair-independently; means for lowering saidplatform toclamppins "standing; on, the alley;

means for actuatingeach of saidfluid pressure extending over the? bed: of" an alley "where pins we spotted; resilient material mounted on" the" underside of saidframe; means for supporting; said 'frame-foi travel toward and ;away' from the bed of a bowlingalley,"pinengaging members movably; mountedwith ;respectto said 1' frame,

cushioning-materialmounted' on the pin enga e ingsurfaceof said-pinengaging members, means ,7 for lowering said frame to "bring theresilient material into holding engagement with the pins standing on; the bowling; alley, V and pneumatic means-constructed and arranged to apply a yield;

ing force-to each of said; pin, engaging. members 7 to -move them independently along, a predeterminedrectilinearpath ofjtraveltq bring at least: twoof said members into yieldable gripping en? gagement with each standing pinv located in, said path of travel.

8: In an1automatic pin setting machine for: bowling alleys, apparatus vfor en a ing; lifting and replacing standingbowling pins on a bowling alley comprising, an elevator mountedfor. movement" toy and froma bowling alley; elongated bowiingpin grippers positioned below, said elevator parallel-to the length1of' thealley and adjacent each of-* they areasion which". bowling pins are spotted; movable arms, depending; from said elevator transversely connected to saidelon= gatedbowling pin grippers for-moving :said grip v pers to getherand apart; said arms "being .;socon= structed :and arranged=that the arms-pf" adjoin ing grippers are aligned lengthwise of the alley,

with the back of each gripper contacting the arm of the adjoining gripper when the grippers are in open position; means for moving said elevator toward a bowling alley to engage and clamp standing pins to the alley, and means for actuating said arms to bring said grippers into gripping engagement with the bowling pins clamped to the alley.

9. In a bowling pin setting machine for use with an alley having a pin supporting bed, apparatus for engaging, lifting and replacing bowling pins on said bed comprising, a frame adapted to move toward and away from the bed of a bowling alley; pairs of pin grippers depending from said frame over each of the pin spot positions on the alley; cylinders having pistons slidably mounted therein for operating each pin gripper independently of the other grippers; means for connecting each of said pistons with one of said pin grippers; means for clamping the standing bowling pins to the bowling alley each time said frame moves toward the bed of the bowling alley, said clamping means being connected to said frame for movement therewith; and means for applying fluid pressure separately to each of said pistons to cause the bowling pin grippers at each pin spot position to move toward each other to engage with standing bowling pins clamped to the bowling alley, said fluid pressure means being so constructed and arranged that when one gripper engages with a clamped bowling pin, it will stop while the other grippers will automatically continue their movement until they either engage standing bowling pins or each other.

10. In an automatic bowling pin setting machine, bowling pin engaging, lifting and replacing apparatus comprising, a support, ten pairs of pin gripping members depending from said support, ten pairs of cylinders for moving each pair of pin gripping members together and apart, pistons slidably mounted in each of said cylinders, connecting mechanism for connecting said pistons to the pin gripping members, and means for simultaneously applying fluid pressure from a single source to all of the cylinders at one time to bring the spaced pin engaging members of each pair together in gripping position.

11. In an automatic pin setting machine for use on bowling alleys, pin engaging, lifting and replacing mechanism comprising, a carrier table having narrow elongated slots formed in said table over each of the areas On a bowling alley where pins are spotted, shanks mounted for movement parallel to said table and extending through said slots, elongated pin engaging members mounted transversely at the lower end of each of said shanks, means for lowering said carrier table toward the bowling alley to engage the table with the tops of bowling pins standing on the alley to hold the same against the alley, and 1 means for bringing said elongated pin engaging members into gripping engagement with the necks of the standing bowling pins held against the alley.

12. Automatic bowlin pin gripping, lifting and respotting apparatus comprising, a platform mounted for movement toward and away from the bed of a bowling alley where bowling pins are positioned, resilient material mounted on and extending over substantially the entire under side of said platform, pairs of parallel rectilinearly movable pin engaging members extending below said platform for engaging the necks of stan mg bowling pins, means for moving said platform toward the alley to embed the heads of standing bowling pins in said resilient material to hold the pins free from lateral displacement, means for moving the pin engaging members of each pair into and out of gripping engagement with the necks of standing bowling pins engaged by said resilient material, and means for moving said platform and the standing bowling pins held between said pin engaging members and said resilient material away from the bowling alley.

13. In an automatic pin setting machine for setting bowling pins on a bowling alley, apparatus for gripping, lifting and replacing standing bowling pins on an alley comprising, a platform mounted for movement to and away from the bed of a bowling alley, opposed pin engaging members positioned above each of the ten pin spot positions on a bowling alley, pressure means employing compressible fluid mounted On said platform for yieldably actuating each of said pin engaging members independently to move said opposed members in opposite directions into yieldable gripping engagement with standing bowling plIlS.

14. In an automatic pin setting machine for setting bowling pins on a bowling alley, apparatus for gripping, lifting and replacing standing bowling pins on an alley comprising, a platform adapted to be moved to and'away from the bed of a bowling alley, pairs of opposed pin gripping members extending below said platform, compressible pneumatic means for yieldably moving each gripper member independently along a predetermined rectilinear path, means for holding standing bowling pins against the bed of a bowling alley, and mechanism for actuating said pneumatic means to cause the grippers of each pair to move in opposite directions along their predetermined paths of travel, to yieldably grip between at least twoopposed grippers any pins standing in their path while they are held against the bed of the bowling alley and apply a predetermined yieldable pressure against any pin so engaged to effect a grip thereon, and means for raising and lowering said platform to lift and replace gripped pins on the bowling alley.

' 15. In an automatic pin setting machine for use on bowling alleys, pin engaging, lifting and replacing mechanism comprising, a carrier table constructed and arranged to travel toward and away from the bed of a bowling alley, a pair of opposed arms depending from said carrier table at each pin spot position on the alley, pin gripping bars mounted transversely on the lower end of said arms and arranged in parallel planes extending lengthwise of the alley, means for movably connecting said arms to the carrier table and offsetting the arms of adjoining pin spot positions with respect to each other to cause the adjoining arms to align with one another lengthwise of the alley when the adjoining bars are back to back and each bar engages the arm supporting the adjacent bar when in their most open position, and means for moving the opposed arms of each pair together to grip a pin between said pin gripping bars and away from each other to release any pin gripped therebetween.

16. Apparatus for gripping, lifting and replacing bowling pins on an alley comprising, a single unitary platform mounted for movement to and away'from a bowling alley, rectilinearly movable arms depending from said platform, horizontal pin engaging members mounted transversely on the lower portions 91 Said arms to form pairs of opposed parallel pin gripping members, means for lowering said platform into contact with standing bowling pins to engage and clamp standing bowling pins to the alley, and means for simultaneously moving the opposed horizontal pin en gaging members by means of said arms into engagement with the clamped bowling pins.

17. Bowling pin engaging, lifting and replacing apparatus comprising, a lower support adapted to travel to and from the bed of a bowling alley, an upper support movably connected to said lower support for travel therewith, pin engaging devices positioned below said lower support and arranged lengthwise of the alley, arms attached to said pin engaging devices, the arms supporting adjoining pin engaging devices being staggered so that each device engages the arm supporting the adjacent device when said devices are back to back in open position, whereby the arms are aligned lengthwise of the alley, and means operated by the relative movement between said upper and lower supports to move said pin engaging devices by means of said arms into and out of engagement with standing bowling pins.

18. A bowling pin handling apparatus comprising, a movable platform positioned above the area of the bowling alley on which bowling pins ar positioned, cushioning material mounted on the side of said platform facing the bowling alley, bowling pin engaging members projecting through said platform and beyond said cushioning material, fluid pressure means for moving pairs of said pin engaging members into and out of pin engaging position, mechanism for actuating said fluid pressure means, and a device for raising and lowering said platform to bring the cushioning material of said platform into and out of clamping engagement with bowling pins standing on a bowling alley.

19. An automatic bowling pin handling apparatus comprising, a platform movable toward 14 and away from a bowling alley, cushioning material mounted on the side of said platform facing the bowling alley, a carriage support connected to said platform, means for mounting said platform and carriage support for movement relative to each other, a plurality of carriages positioned on said carriage support for free movement thereon in a direction parallel to the side of the platform, arms projecting through the platform beyond the cushioning material, pin engaging members mounted at the lower ends of said arms, actuating means interconnecting said carriages with said arms and arranged to be operated by relative movement between said carriage support and said platform to bring together and spread apart said pin engaging members, a control for operating said means for effecting relative movement of said carriage support and platform to bring said pin engaging members into and out of gripping relation with standing bowling pins, and a raising and. lowering mechanism for lowering said platform and cushioning material into engagement with pins standing on a bowling alley to clamp standing pins between said cushioning material and said bowling alley and for raising the platform and the gripped bowling pins to permit removal of fallen pins from the bowling alley.

CHARLES E. SCI-ION.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,584,030 Gray May 11, 1926 2,231,842 Rundell Feb. 11, 1941 2,300,802 Parra et a1 Nov. 3, 1942 2,307,839 Kaufman Jan. 12, 1943 2,316,183 Patterson Apr. 13, 1943 2,388,708 Bates Nov. 13, 1945 2,530,385 Frye Nov. 21, 1950 

